Examples of conventional rotary table systems of the type described above are disclosed in Patent Documents 1 and 2. The rotary table system disclosed in Patent Document 1 has a base, a rotary table rotated about a predetermined center of rotation set on the base, and a rotation driving mechanism having a rotation guide installed between the base and the rotary table and a rotation driving source that drives the rotary table to rotate through the rotation guide. The rotation guide includes a ring-shaped endless track formed from a plurality of track members, and a plurality of guide units sliding along the track. The rotary table is mounted on the plurality of guide units.
The rotary table system disclosed in Patent Document 2 includes a curvilinear guide apparatus having a plurality of slides movably attached to a ring-shaped integrated endless track rail with a multiplicity of rolling elements interposed therebetween so that the slides slide along the endless track rail. A table is secured to the plurality of slides of the curvilinear guide apparatus. Thus, the table is rotatably supported by a fixed bed through the curvilinear guide apparatus.    Patent Document 1:
Japanese Patent Application Publication No. Hei 9-125736    Patent Document 2:
Japanese Patent Application Publication No. Hei 8-21440